On another forum in the thread on YouTube write that on the contrary GSA backlinks are working.
Here is just a confident statement that backlinks are not working. On what basis are your conclusions ? Do you have their YouTube channels ? To say that GSA is not working ?

YouTube SEO is very much like website SEO. You need to include keywords you aim to rank by to the video title and description, add proper tags.
It is also necessary to add a few links to the description (to your channel, to playlists, to social networks etc.)

Share the link in social media, in such a way you will get some backlinks.